Automatic choke



Feb. 15, 1938. J E. ROUALET 2,108,296

AUTOMATIC CHOKE Filed May 18, 193] IN VEN TOR.

ANDRE d. E. ROUALET Patented Feb. 15, 1938 UNITED STATES PATENT OFFICEAUTOMATIC CHOKE Andre J. E. Roualet, D Chrysler Corporation, ration ofDelaware etroit, Mich., assignor to Detroit, Mich a corpo- ApplicationMay 18, 1931, Serial No. 538,133

13 Claims.

5 bustion engine, particularly during starting thereof and during thewarming up stages which follow starting.

An internal combustion engine can not always be started when the chokevalve is completely l0 closed or at any one predetermined position. The

position at which the choke valve must be set depends upon thetemperature ofthe engine at the time it is started. For this reason,fully automatic choke regulating mechanism must be capable ofpredetermining the closed positions of the choke valve with respect tothe temperature of the engine, in addition to gradually opening thechoke valve as the temperature rises after the engine is started. Themain objects of the invention are to provide carburetor chokingapparatus which is fully automatic in its'operation to the extent ofrequirlng no manual effort or attention in addition to that employed inbringing the conventional e e starting mechanism into operation; toprovide means of this kind which holds the choke valve of a carburetorin a predetermined closed position while the starting mechanism 01' anenglue is operated; to provide thermostatic mechanism for predeterminingthe closed positions of the choke valve with respect to the temperatureof the engine so as to prevent overloading of the carburetor duringstarting of the engine at various temperatures; to provide temperatureresponsive mechanism of this kind whlchalso predetermines the initialdegree of opening of the choke valve immediately after operation of thestarting mechanism is discontinued following the occurrence of the firstexplosions; and to provide v regulating means of this character which isadapted to gradually open the choke valve from its initial open positionto a full open position during the warming up stage of the engine. I 7An illustrative embodiment of the invention 46 is shown in theaccompanying drawing, in which:

Fig. 1 is a fragmentary elevation. of a. vehicle engine showing myimproved choke regulating mechanism, partly in section, and illustratingdiagrammatically, its connection with the starting mechanism of theengine.

Fig. 2 is a horizontal section of'the choke yalve regulating mechanismtaken ,on the line 2-2 of Fig. 1. v

Fi is a vertical section of the choke valve regulating mechanism showingthe relative position of the parts thereof when the circuit of thestarting mechanism is closed while the engine is at an elevatedtemperature.

Fig. 4 is a transverse horizontal section taken on the line 4'4 of Fig.3.

Fig. 5 is a vertical section taken on the line '5-5 of Fig. 3. I

Fig. 6 is a fragmentary vertical sectional view taken on the line 6-6 ofFig. 2.

In the form shown, the invention is illustrated in connection with 'aninternal combustion engine which includes a cylinder head I, an exhaustmanifold 2 and an intake manifold 3. Communicating with the intakemanifold 3 is an air passage 4 of a carburetor 5 of conventionalconstruction having an air inlet 6 which is provided I with a butterflytype of choke .valve 1. The choke valve is carried on a shaft 8 which isJournaled in apertures in the respectively opposite sides of the airinlet 6 and which is eccentrically located on the choke valve. Thesuction in the air passage 4 of the carburetor normally I urges thechoke valve in a counterclockwise direction toward its open position.

Formed in the choke valve are a plurality of apertures or air passagesl0 which provide an auxiliary air inlet to the carburetor. An auxiliaryvalve including a disc ll having a stem l2 thereon which is slidablymounted in an aperture ii in the choke valve 1, is carried by the lattervalve and is provided with a coil spring l4 which bears between one sideof the choke valve and a washer IS on the free end of the valve stem.The auxiliary valve is unobstructed and free to open under the controlof the carburetor suction when the choke valve 1 is closed. The springl4 and the apertures III are correspondingly calibrated so as to admitthe correct amount of air under the force of the suction which iscreated in the air passage 4 during the cranking operation of theengine, so as to produce in conjunction with the fuel which is fed intothe air passage 4 by the suction therein, a fuel mixture which hassuitable explosive properties for efiecting the initial explosions ofthe engine during cold starting.

The choke valve I is provided with automatic regulating mechanism whichincludes a casing or housing I6 having side flanges I! by which thehousing is rigidly mounted on the cylinder head I of the internalcombustion engine by bolts l8. The housing extends downwardly at theside of the cylinder head i and is located directly over the exhaustmanifold 2.

Mounted in the casing i6 is a solenoid l9 hav ing one grounded terminaland another terminal 26 which is electrically connected by a conductor2| with one contact element of a starter switch 22. The starter switchis electrically connected with a battery 23 of which one terminal isgrounded at 24 and it may be closed by depression of a starter pedal 25which simultaneously energizes the solenoid l9 and the starter motor 26.

The armature 21, including a flat plate 28 in which is formed alongitudinal slot 29, is pivotally mounted at 38 upon a bracket 3| whichis rigidly secured to an end wall of the casing l6. A spring 30' whichbears between the end wall of the casing and the lower side of thearmature 21 normally urges the latter about its pivotal axis in acounterclockwise direction. This armature extends over the solenoid l9and it has an external, downwardly extending arm 32 which extendsthrough a slot 33 in the wall of the casing. The external end of the arm32 is connected by an adjustable link 34 with a crank arm 35 on theshaft 8 of the choke valve 1. When the solenoid I9 is energized, thearmature .21 is rotated in a clockwise direction against the action ofthe spring 30' so as to turn the choke valve 1 toward a closed position.

The automatic valve regulating apparatus is provided with controlmechanism which co-acts with the armature 21 so as to regulate bothclosing and opening of the choke valve. This mechanism includes avertically shiftable bar 36 which extends through registering aperturesin a reversely bent end portion of a bracket 31 that is mounted in thecasing and below the solenoid IS. The bar extends upwardly through thelongitudinal slot 29 of the plate 28 of the armature and is normallyurged upwardly by a spring 38 which bears between the bracket 31 and awasher 39 which is secured against upward movement on the bar 36 by apin 40. The upper end of the bar 36 registers with a set screw 4| whichis adjustably threaded in the cover 42 of the casing l6 so as topositively limit upward movement of the bar. Formed on the lower end ofthe bar 36 is a flange 43 in which is adjustably threaded a set screw44.

The extremity of the adjustable set screw 44 on the bar 36 registerswith one extremity of a thermostatic element 45 which preferablyincludes a coiled bi-metallic member and which is located in the casingl6 in close proximity to abut spot 46 on the exhaust manifold 2. Thethermostatic element 45 holds the shiftable bar 36 in various positionsagainst upward movement under the action of the spring 38 so as topredetermine its position with respect to the temperature of the engine.Mounted in the upper end portion of the bar 36 is a pin 46 which extendsoutwardly beyond the edges of the slot 29 in the plate 28 and limitsupward rotation of the armature. When the solenoid I9 is de-energized,the armature 21 rotates in a counterclockwise direction until it engagesthe pin 46 which is spaced sufficiently from the lowermost position ofthe plate 28 of the armature to permit an initial, rapid partial openingof the choke valve 1 as soon as operation of the starting system isdiscontinued after the first explosions of the engine. The degree ofinitial opening is predetermined with respect to the temperature of theengine by the thermostatic element 45 which predetermines the positionof the shiftable bar 38 and pin 46 with respect to the plate 28 of thearmature 21. Further opening of the choke valve beyond the initiallyopen position occurs gradually under control of the thermostatic element45 as the temperature of the engine rises.

In order to properly position the choke valve for starting the enginewhile it is at various temperatures, it is necessary to interrupt theclockwise rotation of the armature 21 at various positions dependingupon the temperature of the engine at the time the solenoid isenergized. This is expediently accompanied by the stop lever 41 which ispivotally secured at one end in a. slot 48 in the bar 36 by a pin 49.The stop lever 41 is located in the longitudinal slot 29 in the plate 28of the armature and it has an enlarged head 50 at its free extremitywhich is located between the core 5| of the solenoid l9 and a downwardlybent portion of an inclined lip 52 that is integral with the plate 28 ofthe armature. The enlarged head 50 of the stop lever 41 has a curvedperiphery which rests at one side upon the core 5| of the solenoid andregisters at its other side with the edge of the inclined lip 52. As thepivoted end of the stop lever 41 'is raised and lowered in unison withthe shiftable bar 36, the enlarged head 50 is shifted and rocked uponthe core 5| of the solenoid so as to bring the extremity of the lip 52into contact with the periphery of the head at various positions whenthe solenoid is en ized to close the choke valve at different enginemperatures. Engagement of the extremity of the lip 52 with the enlargedhead of the stop lever 41 arrests the downward movement of the armatureso as to hold the choke valve in predetermined partially open"-positionswhich vary in degree in direct proportion to the engine temperature.

In operation, when the engine is extremely cold, the shiftable bar 36and the stop lever 41 are held in the positions shown in Fig. 1 by thethermostatic element 45 so as to permit the armature to be rotated toits extreme lower position when the solenoid i9 is energized, so as tosubstantially completely close the choke valve 1. When operation of thestarting mechanism is discontinued following the first explosions of theengine, the solenoid I9 is lie-energized and the armature is allowed torapidly rotate in a counterclockwise direction, under the combinedinfluence of the spring 30' and the suction on the eccentrirotation soas to retain the choke valve 1 in an initial partially open position.Further opening of the valve from the initially open position to a fullopen position occurs gradually under control of the thermostaticelement.

When the engine is at. a predetermined temperature, the shiftable bar 36and stop lever 41 are held 'by the thermostatic element 45 in theposition shown in Fig. 3 wherein the portions of the periphery of theenlarged head 50 which contact with the core 5| of the solenoid andregister with the extremity of the inclined lip 52 respectively, arespaced apart sufiiciently to either completely prevent rotation of thearmature or to hold it against rotation beyond a predetermined position.In practice, it isfound that complete closing of the choke valve may beallowed during starting under engine temperatures of 65 F., andtherefore the contour of the enlarged head 58 of the stop lever ispreferably formed so as to prevent complete closing of the choke valveat or above engine temperature of 65. The curvature of the periphery ofthe enlarged head 50 is also suitably formed so as to predetermine theposition at which downward rotation of the armature is interrupted inproportion to the engine temperature during starting above the selectedtemperature.

In this manner, the carburetor is conditioned said operating lever toproduce various predetermined fuel mixtures during starting at specifiedengine temperatures 7 within a substantially large range, the air factorof the fuel mixture being dependent upon the contour of the periphery ofthe head 50 of the stop lever and the characteristics of thethermostatic element 45.

Although but one specific embodiment of this invention has herein beenshown and described, it will be understood that various changes in thesize, shape and arrangement of parts may be made without departing fromthe spirit of my invention and it is not my intention to limit its scopeother than by the terms of the appended claims.

What I claim is:

1. In an internal combustion engine unit comprising a carburetor havinga choke valve and having operating means for urging said valve toward aclosed position to condition said engine for starting; means forpredetermining the opening and closing movements of said valve withrespect to the temperature of said engine including variable meanshaving a member constructed and arranged to positively limit closing ofsaid choke valve by said operating means; a member carried by saidvariable means for regulating opening of said choke valve afteractuation of said operating means is discontinued; and a temperatureresponsive means disposed ad ac nt said engine andd rectly subjected totemperature changes thereof and coacting with said variable means forcontrolling the position of said memb rs.

2. In an internal combustion engine including starting mechanism and acarburetor having a valve for controlling the admission of air to saidcarburetor and having means forautomatically mnv ng said valve toward aclosed position hen said, engine is started, control means including avariable stop for positively arresting the operation of said valveclosing mechanism and adapted to limit closing of said valve thereby atvarious positions and including an element for regulating the opening ofsaid valve, and a single thermostat for varying the positions of saidstop and said element in accordance with the temperature rise of saidengine.

I 3. Choke valve operating mechanism including asupport, an operatinglever pivotally mounted on said support and pivotally connected withsaid choke valve, actuating means for rotating so as to move said chokevalve toward a closed position, means for urg-, ing said lever in anopposite direction so as to move said choke valve toward a fully openposition when said actuating means is inoperative, control apparatushaving a member for limiting rotation of said lever by said actuatingmeans at various positions so as to predetermine the position of said.valve with respect to the temperature to which said control apparatus issubjected, an element on said control apparatus for regulating theopening of said choke valve, and a single thermostat for actuating saidcontrol apparatus.

4. Choke valve operating mechanism including a support, an operatinglever pivotally mounted on said support and connected with said chokevalve, actuating means including a'solenoid for rotating said operatinglever so as to move said choke valve toward a closed position, a barshiftably mounted on said support, a stop arm pivotally mounted on saidbar including an enlarged head having a curved periphery, the peripheryof said head being in registration with said operating lever, yieldablemeans co-acting with said shiftable bar for normally holding said stoparm in an operative position, and a thermostat element for movingsaid'bar against the action of said yieldable means so as to vary thelimiting position of the periphery of said enlarged head with respect tosaid lever in proportion to the temperature to which said thermostaticelement is subjected.

5. In combination with an internal combustion engine having a,carburetor provided with a choke valve, choke valve operating mechanismincluding a casing having a compartment provided with an open endadjacent a portion of said engine which is subjected to heat duringoperation of the latter, an operating lever pivotally mounted in saidcasing, means for operatively connecting said lever and said chokevalve, actuating means for rotating said operating lever so as to movesaid choke valve toward a closed position, means for urging said chokevalve toward a fully open position when said actuating means isinoperative, a temperature responsive device in said compartmentadjacent the open end thereof, and a control member movable by saidtemperature responsive device, having an element thereon provided with acurved periphery engageable by said operating lever for -limitingrotation thereof by said actuating means in one direction so as topredetermine the closed positions of said engine which is subjectedto'heat during operation of the latter, an operating lever pivotallymounted in said casing and connected, with said choke valve, actuatingmeans including a solenoid for rotating said operating lever so as tomove said choke valve towarda closed position, a bar shiftably mountedin said casing, a .stop arm pivotally mounted on said bar including ahead portion having a curved periphery, the periphery of said head beingengageable by said operating lever, yieldable means cooperating withsaid shiftable bar for normally holding said stop arm in an inoperativeposition, and a thermostat element for moving said bar against theaction of said yieldable means so as to vary the limiting position ofthe periphery of said head with re spect to said lever in proportion tothe'temperature'of said engine.

7. In combination with an internal combustion engine having a carburetorprovided with a choke valve, choke valve operating mechanism including acasing having a compartment provided with an open end adjacent a portionof said engine which is subjected to'heat during operation of thelatter, a lever pivotally mounted in said casing and connected with saidchoke valve,

'vided with an open end adjacent a portion of said member movable bysaid temperature responsive means and engageable between a portion ofsaid lever and said actuating means for predetermining the degree towhich said valve is closed by operation of said actuating means.

3. In combination with an internal combustion engine having a carburetorprovided with a choke valve, choke valve operating mechanism including acasing having a compartment provided with an open end adjacent a portionof said engine which is subjected to heat during operation of thelatter, a lever pivotally mounted in said casing and connected with saidchoke valve, actuating means for rotating said lever in one direction soas to urge said choke valve toward a closed position to condition saidengine for starting, resilient means urging said lever in an oppositedirection, control -mechanism having a temperature responsive elementlocated in said open-end compartment and having a shiftable membermovable by said temperature responsive means andengageable with saidlever for predetermining the degree to which said valve is closed byoperation of said actuating means, said shiftable member being providedwith a stop engageable with said lever for predetermining the degree towhich said valve can be opened when said actuating means is inoperative.

9. Choke valve operating mechanism including a support, an operatinglever pivotally mounted on said support and connected with said chokevalve, actuating means including a solenoid for rotating said operatinglever so as to move said choke valve toward a closed position, a barshiftably mounted on said support, a stop arm pivotally mounted on saidbar including an enlarged head having a curved periphery, the peripheryof said head being in registration with one side of said operating leverfor limiting valve closing movements of said lever, an element on saidshiftable bar for regulating valve opening movements of said lever,yieldable means coacting with said shiftable bar for normally urging thelatter in one direction, and a temperature responsive device for movingsaid bar against the action of said yieldable means so as to vary thelimiting position of said stop arm with respect to said lever and tobring said valve opening regulating element into operative relation withsaid lever.

10. Choke valve operating mechanism including a support, an operatinglever pivotally mounted on said support and connected with said chokevalve, actuatingmeans for rotating said operating lever so as to movesaid choke valve toward a closed position, a bar shiftably mounted onsaid support, a stop arm pivotally mounted on said bar including anenlarged head having a curved periphery, the periphery of said headbeing in registration with said operating lever, yieldable meanscoacting with said shiftable bar for normally holding said stop arm inan operative position, and a thermostat element for moving said baragainst the action of said yieldable means so as to vary the limitingposition of the periphery of said enlarged head with respect to saidlever in proportion to the temperature to which said thermostaticelement is subjected.

11. Choke valve operating mechanism including a support, actuating meansincluding a solenoid mounted on said support and a lever extendingadjacent the core of said solenoid, said lever being operativelyconnected with said choke valve, a bar shiftably mounted on saidsupport, a stop arm pivotally mounted on said bar having a curv edperipheral portion and extending between a portion of said lever and thecore of said solenoid, yieldable means coacting with said shiftable barfor normally holding said stop arm in an operative position, and athermostat element for moving said bar against the action of saidyieldable means so as to vary the limiting position of the periphery ofsaid enlarged head with respect to said lever in proportion to thetemperature to which said thermostatic element is subjected.

12'. A device for controlling the choke-valve of an internal combustionengine, comprising an electro-magnet having a pole-piece, a movablearmature associated with said electro-magnet and arranged to be movedtoward said pole-piece when the magnet is energized, said armature beingadapted for connection to the choke-valve to move the choke-valve towardclosedp'osition when the armature is moved toward said polerpiece, atemperature-responsive element, a movable stop disposed between saidpole-piece and said armature, an operative connection between said stopand said temperature-responsive element whereby said stop will becontrolled by said element to vary the extent to which said armatureapproaches the pole-piece when the magnet is energized, and meansoperated by said tempera'ture-responsive element for limiting movementof said armature away from said pole piece.

,13. In combination with an internal combustion engine having acarburetor provided with a choke valve and a control device for saidvalve, mechanism for operating said device comprising a lever, means foroperating said lever to close said valve when the engine is cold, arecipro- ,cable member operatively associated with said lever, athermostat for actuating said reciprocable member, and a cam pivoted tosaid reciprocable member in the path of movement of a portion of saidlever to prevent said valve from closing when the engine is hot.

ANDRE J. E. ROUALET.

